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On Alpha VMS, a negative zero value may be generated when the user
expects a zero result.  The negative zero value is not equivalent to
zero.  This behavior may produce incorrect results when doing a
comparison to zero.

The following sample code demonstrates the problem.  In the data set
B, 0*(-1) should return a result of zero, and the subsequent MERGE
should produce one observation.  On Alpha VMS, the MERGE produces two
observations because the result 0*(-1) is negative zero.

  DATA A;
    X=0;
  RUN;
  DATA B;
    X=0*(-1);
  RUN;
  DATA C;
    MERGE A B;
    BY X;
  RUN;


A circumvention is to specify the system option NOCODEGEN for any job
that encounters the problem.


A Technical Support hot fix for Release 8.1 TSLEVEL TS1M0 for this
issue is available at:

http://www.sas.com/techsup/download/hotfix/81_sbcs_prod_list.html#004820


A Technical Support hot fix for Release 8.2 TSLEVEL TS2M0 for this
issue is available at:

http://www.sas.com/techsup/download/hotfix/82_sbcs_prod_list.html#004820

For customers running SAS with Asian Language Support (DBCS), this
hot fix should be downloaded from:

http://www.sas.com/techsup/download/hotfix/82_dbcs_prod_list.html#004820

Operating System and Release Information

A fix for Release 8.1 (TS1M0) for this issue is available at:

A fix for Release 8.2 (TS2M0) for this issue is available at:

A fix for Release 8.2 (TS2M0) with Asian Language Support (DBCS) for this issue is available at: